1. Field of the Invention
The invention relates an acoustic therapy apparatus with an electro-acoustic transducer for producing focused sound waves to be transmitted onto the body of a patient via coupling media. The coupling media and the transducer, where appropriate, in combination with parts of a transducer housing, form a shell and comprise a carrier equipped with transducer elements. Sound waves exiting the sound irradiation surface are directly coupled into a coupling element which bears on this irradiation surface, is fixedly allocated to the transducer and forms a first sound advance path. After running through the coupling element the sound waves are further coupled into an elastic coupling cushion which is to be applied on to the patient body, is releasably connected to the coupling element and forms a second acoustic sound advance path. The length of the respective external sound advance path and thus the penetration depth of the sound waves into the patient body is variable by using one of several available coupling cushions of various thicknesses:
2. Description of the Related Art
Most of the apparatus described above are equipped with self-focused transducers where it is particularly important to bring the transducer focus coincident with the treatment location in the patient body. In an apparatus with a stationary transducer focus, this may be problematic since the objects to be irradiated with sound.
For this reason the apparatus is modified so that the sound advance path i.e., the path between the sound irradiation surface of the transducer and the surface at which the sound is coupled into the body of the patient is variable. For this purpose the apparatus are provided with at least one coupling element having an end surface on the transducer irradiation surface and an other end surface forming a coupling surface to be applied onto the patient body.
The length of the advance path is determined by the respective distance between the two mentioned end surfaces, by which means the distance between the coupling surface of the coupling element and the transducer focus, as well as the respective penetration depth or position of the sound wave focus in the patient body, is predetermined. The mentioned distances and the sound penetration depth may be changed by variation of the length of the sound advance path.
German reference DE 195 09 004 C1 discloses exchangeable coupling elements having different thicknesses and that form sound advance paths that vary in length. In each case, one shape stable and elastic coupling element selected with respect to a suitable advance path is incorporated into the transducer shell in an axially aligned manner such that its end surface as a or interior surface comes to bear against the sound irradiation surface of the transducer whilst the oppositely lying end surface located outside the transducer shell or transducer housing serves as a sound coupling surface via which the sound is irradiated and coupled into the patient body in a focused manner.
With this known therapy apparatus a transition free of air bubbles between the sound irradiation surface and the coupling element even with the additional application of a coupling gel may be difficult to achieve. Furthermore the large-volumed coupling elements consisting of a hydro-gel have quite a large weight which is why they are difficult to manipulate during assembly and disassembly.
German reference DE 33 12 014 A1 discloses a therapy apparatus. with which a relatively large volumed coupling element is permanently and rigidly allocated to the transducer and further light coupling cushions of various thicknesses in the form of elastic disks may be exchangeably connected to the coupling element. In this case the effective length of the sound advance path is determined by the sum of the thicknesses of the coupling element and of the coupling cushion and is variable by using coupling cushions of differing thicknesses.
Air bubbles in the region of the sound transition from the sound irradiation surface of the transducer to the coupling element are also expected after incorporation of the coupling element into the transducer shell. These air bubbles, which disturb sound propagation may not be alleviated when the elastic coupling element is rigidly pressed against the sound irradiation surface. Furthermore, germs can get into the region between the transducer or transducer housing and the coupling element so that it becomes necessary to periodically remove and disassemble the coupling element to clean and sterilize it.
German reference DE 33 19 87 102 discloses a therapy apparatus including an advance path of soft plastic and a coupling cushion filled with water for coupling the sound waves into the body of the patient. For the purpose of varying the penetration depth of the therapy waves, the water volume in the coupling cushion must be varied via a compensation vessel. It is particularly difficult to fill the spherical calotte and transducer shell with the plastic since the plastic filling projects relatively far beyond the transducer shell to the outside in the sound direction. On the side facing the coupling cushion, the coupling element must be formed convexly or conically in a projecting manner in order to let air bubbles in the coupling cushion or coupling pillow wander laterally out of the sound field. As with all therapy apparatus functioning with water as a coupling medium, one must also deal with the possibility of contaminated water.
The object of the present invention is to overcome the disadvantages of the prior art.
Another object of the present invention is to provide a therapy apparatus that is easy to manipulate and does not have air bubbles.
A further object of the present invention is to provide a therapy apparatus whereby cleaning and sterilization of the coupling element can be performed while the coupling element remains in the transducer shell.
These objects are achieved in the present invention whereby the transducer shell, with the material of the coupling element, is permanently cast flush with the edge and filled out. The casting of the transducer shell is performed under a vacuum so that the material of the coupling element gets into contact with the transducer shell surface without air bubbles and assumes a permanent adhesive connection to it.
If the coupling element fills out the transducer shell flush with the edge a planar or when required a slightly curved coupling surface of the coupling element, results that is easy to clean and, where required, is easy to sterilize.
The transducer shell may simply be completely filled out with the material of the coupling element, and subsequent to this the transducer shell and the surface is removed of its filling in a planar manner with a spatula so that there arises a surface which occludes flush with the edge of the transducer shell. It is also ensured that the filling mass remains shape stable in the transducer shell. If the coupling element incorporated in this manner into the transducer shell becomes damaged material may simply be in the region of such damage and brushed smooth so that repairs are possible in a simple and inexpensive manner.
As has already been mentioned the coupling surface of the coupling element located in the transducer shell may also be curved slightly in a convex or concave manner. However, a planar coupling surface is preferred since it offers the smallest possible surface and thus the danger that air bubbles remain between the coupling element and the coupling cushion to be laid onto this is reduced to is minimized.
Hydro-gels and the like are a suitable material for the coupling element and the coupling cushion. A polyacrylamide agar gel is preferred. Furthermore, technical silicon gel materials, synthetic rubber materials and polyurethane materials are particularly suited to this use as they set well and possess the necessary elasticity. In any case, the coupling element may be formed of a hard elastic and the coupling element may be formed of a soft elastic. It is sufficient to determine the position of the therapy zone with a standard ultrasound locating apparatus and to mark this on the patient body using target marking and then to apply the suitable coupling cushion.
The releasable connection of the coupling cushion to the coupling element is then created such that the coupling surface of the coupling element and the interior coupling surface of the coupling cushion, are connectable by an adhesive effect produced by a vacuum between these two surfaces. This may be effected via a suction pad effect if, for example, the coupling surface of the coupling element is planar and the coupling-in surface of the coupling cushion is concave or, conversely if the coupling surface of the coupling element is concave and the coupling surface of the coupling cushion is planar, in which case the two surfaces by way of pressure on the coupling cushion are brought into mutual bearing on one another in a close and bubble-free manner and are held together by the suction effect.
In the coupling element there may also be formed suction channels which end in the coupling surface of the coupling element and may be connected via a valve to a suction pump, through which either air or water as a coupling medium is suctioned from between the coupling cushion and the coupling element. A vacuum between the coupling cushion and the coupling element which is required for the adhesive connection is thus maintained.
Furthermore, the transducer housing accommodating the carrier with the transducer elements should laterally encase the coupling element so that in this case the transducer shell below is limited by the sound irradiation surface and laterally by the transducer housing.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further noted that the drawings are merely intended to conceptually illustrate the structures and procedures described herein.